/Engine/Source/Editor/UnrealEd/Classes/Editor/UnrealEdEngine.h
Returns the configuration of attachment that would result from calling AttachSelectedActors at this point in time
[AActor](API\Runtime\Engine\GameFramework\AActor) * GetDesiredAttachmentState ( [TArray](API\Runtime\Core\Containers\TArray)< [AActor](API\Runtime\Engine\GameFramework\AActor) * > & OutNewChildren )